I. Field of the Invention
The present invention relates generally to a system and methods aimed at surgery, and more particularly to system and methods for nerve testing during anterior surgery, including but not limited to anterior disc replacement surgery, nucleus replacement, and interbody fusion.
II. Discussion of the Prior Art
Performing various surgical procedures, including but not necessarily limited to total disc replacement, nucleus replacement, and interbody fusion utilizing an anterior approach provides an advantage over other approaches. Exposing the front of the spine, as opposed to the side or the back, generally allows for a more complete excision of the damaged disc.
Utilizing this advantage however may be complicated. Removing too much of a disc may leave adjacent nerve roots exposed to the danger of surgical tools used in disc preparation or disc implants inadvertently contacting the nerve and resulting in pain or nerve damage to the patient. Thus it is difficult to remove as much of a disc as the surgeon would generally
To facilitate the process of disc space preparation and/or implant introduction, it is common to employ a distraction instrument to bias the vertebral bodies on either side of an intervertebral disc away from one another. In so doing, the amount of space between the vertebral bodies is increased, which makes it easier to remove disc material and introduce implants therebetween. One challenge that exits with distracting the vertebral bodies in this manner is that the nerves associated with the particular spinal level can become overstretched during periods of distraction. This may result in neurological impairment (temporary or permanent) for the patient, which can be painful and disruptive to the patient.
Depending upon the type of implant and procedure, a surgeon may elect to compress the vertebral bodies back towards one another after the introduction of the implant. An example would be in a so-called “360 degree” surgery, wherein a fusion implant is introduced into the disc space and a posterior instrumentation system (such as a pedicle screw system) is employed to affix the posterior column of the spine. During such procedures, it is not uncommon to undertake compression of the vertebral bodies towards one another, which can restore spinal alignment and ensure the implant is properly positioned. One challenge that exists with compressing the vertebral bodies together is that the nerves associated with that particular spinal level may become impinged by the vertebral bodies, other boney aspects of the spine, and/or the implants themselves.
The present invention is directed at addressing the above identified challenges.